Physics
Scientific paper
Dec 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001agufmsm51b0831w&link_type=abstract
American Geophysical Union, Fall Meeting 2001, abstract #SM51B-0831
Physics
2407 Auroral Ionosphere (2704), 7831 Laboratory Studies
Scientific paper
In earlier work we described a laboratory-based experimental series whose purpose was to measure ion Joule heating in the presence of a potential profile with a single peak{ 1}. As a part of this effort we demonstrated the ability to control the magnitude and direction of the electric field (or the sign of potential change) in space in a simulated ionospheric environment, in addition to producing ion heating consistent with the calculated Joule heating rate as a function of ion-neutral collisions. Since Joule heating is often regarded as an important mechanism which contributes to energization of outflowing heavy ions observed by high altitude auroral satellites, the understanding of this mechanism in differently structured electric field environments is important. Earlier laboratory studies demonstrated a transition from ion cyclotron wave heating in the presence of transverse dc electric fields to Joule heating as a function ion neutral collision frequency. Our ultimate aim is to fully characterize the effect of electric field structure on the Joule heating by varying the localization of the fields (e.g., creating multiply-peaked potential distributions, varying the scale size of the field, etc) and by allowing the potentials to have a time-dependent amplitude. In space, this implies multiple localized structuring and in time it implies a frequency variation from the ELF range to the ion plasma frequency. In results presented here, we have increased the data sample and varied the spatial size of the fields. In a few instances we have produced doubly-peaked potential profiles. Consistent with earlier results, we have been able to demonstrate a peak in the ion temperature as a function of collision frequency. The data indicate that for approximately constant pressure and electric field, the normalized ion temperature increases with the scale size of the electric field region but early analysis suggests a limit to this increase (for a given scale size). We base this conclusion on a characterization of the scale size which uses the frequency-width-at-half-maximum (fwhm) as a marker of electric field spatial size. *Work supported by ONR; { 1}J. Geophys. Res., 106, 1807, 2001
Amatucci William E.
Ganguli Gurudas I.
Walker Danny N.
No associations
LandOfFree
Electric field scale size influence on ion Joule heating II: An expanded data set* does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Electric field scale size influence on ion Joule heating II: An expanded data set*, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electric field scale size influence on ion Joule heating II: An expanded data set* will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1385955